1. Field of the Invention
This invention in general relates to photographic apparatus and more specifically to an adapter by which a photographic motion picture camera can be coupled to an optical viewing device such as an endoscope to permit simultaneous viewing and photographing of the image formed by an eyepiece of the viewing device.
2. Description of the Prior Art
Endoscopes are optical viewing devices well known to the medical profession for their usefulness in diagnosing disease. With an endoscope, a physician, typically a surgical consultant, visually examines the interior of a patient's body organs for pathological processes whose presence is suspected or indicated by clinical and laboratory findings.
Once detected, a pathology is then carefully studied to determine its precise nature and extent so that the proper course of treatment can be decided upon and recommended to the patient.
For a variety of reasons, it is often advantageous for the surgical consultant to have a permanent photographic record of the endoscopic findings. For example, such records are useful for educational purposes. Also, they can form part of the patient's permanent medical record or can be used as a basis for evaluating changes in the pathology. Additionally, endoscopic photographs serve as a powerful tool for promoting communication between the examining physician and others involved or interested in the diagnosis and as a means for informing the patient about the nature of his illness.
Although endoscopic photographs have their beneficial uses, they are somewhat difficult to obtain because the clinical form of most endoscopes generally is unsuitable for photography, because of the requirements of medically sound and safe practice, and because of the overriding concern for patient safety and comfort.
Photographic and optical principles, for instance, demand that any camera chosen for use with an endoscope must be able to be focused on the image provided by the endoscope's eyepiece, that adequate lighting be provided to assure acceptably exposed photographs, and that the examining physician, and sometimes more than one, be able to see an image of the field under examination immediately before and after a picture is taken in case of stills and continuously in the case of motion pictures. And all of this must be accomplished by apparatus which ideally shares the endoscope's single optical path.
Sound clinical procedure, on the other hand, imposes certain design constraints which makes it difficult to satisfy the photographic and optical requirements of endoscopic apparatus. One major obstacle, for example, is the clinical desirability of using only one endoscope for both the visual clinical examination and the photographic work. It is neither convenient for the examining physician nor fair to the patient to have to withdraw the clinical endoscope once a pathology has been located, insert the photographic endoscope, photograph the field of interest, withdraw the photographic endoscope and reinsert the clinical endoscope. A process like this would obviously complicate an endoscopic examination by adding additional risk and discomfort to what inherently can be an uncomfortable ordeal. Also, since the endoscope must be manipulated quite a bit throughout the examination, any photographic apparatus designed for use with the clinical endoscope should not hamper the physician's freedom of movement or require extensive operations involving attachment and detachment of the photographic apparatus with the endoscope.
Consequently, apparatus used for endoscopic photography must be easy to use, i.e. manipulate, must not unduly prolong the endoscopic examination, ideally, should be mechanically and optically compatible with an existing form of clinical endoscope and, as well, must be capable of reliably producing photographs which are acceptably exposed while containing adequate detail.
Finally, such apparatus must be absolutely safe and must, in particular, be free from any danger of causing electrical shock or creating unduly high temperatures which may come into contact with the patient.
Given the above general considerations, it is evident that the problems associated with providing apparatus for use in endoscopic photography are varied--involving both technical and humane considerations. In the past, these problems have been dealt with in a variety of ways by providing either specially designed photographic systems whose use is limited to endoscopic photography or by providing adapters by which existing cameras can be used with an existing endoscope. For examples reference may be had to U.S. Pat. No. 3,368,643 issued to John E. Hotchkiss on Feb. 1, 1972 and entitled "Endoscope For Photographic Recording"; U.S. Pat. No. 3,918,072 issued to Toshihiro Imai et. al. on Nov. 4, 1975 and entitled "Single-Lens Reflex Optical System For An Endoscope"; U.S. Pat. No. 3,995,287 issued to Karl Storz on Nov. 30, 1976 and entitled "Endoscopic Camera"; U.S. Pat. No. 3,900,021 issued to Anthony Peter Walter Makepeace et. al. on Aug. 19, 1975 and entitled "Coupling for Endoscopes And Instruments Particularly Camera"; U.S. Pat. No. 3,994,288 issued to Joseph G. Stumpf on Nov. 30, 1976 and entitled "Colposcope", and an Article by Brian Stanford which appears in The Journal of Photographic Science, volume 3, 1955, and is entitled "Theoretical First Principles of Endoscopic Photography".
However, none of the foregoing publications appear to deal directly with the specific problem with which the present invention is concerned. In particular, the primary object of the present invention is to provide an adapter by which a motion picture camera of the type having a reflex viewing system which has an entrance pupil that occupies only a portion of the entrance pupil of the camera taking lens and has a central axis which is laterally offset with respect to the optical axis of the camera taking lens can be joined to the proximal end of an optical viewing device such as an endoscope so that the image of an object formed by the viewing device can be viewed and photographed simultaneously wherein the viewing device is of the type which has an eyepiece located at its proximal end for forming a collimated to nearly collimated object image which is visible through an exit pupil spaced behind the eyepiece and subtends an angular field at the exit pupil which is smaller than the angular field of view of the camera taking lens and viewing system.
Although none of the aforementioned publications appear to provide apparatus by which the primary object of the present invention can be accomplished, there is described in U.S. patent application Ser. No. 918,779, filed on June 26, 1978 in the name of William T. Plummer and entitled "An Adapter For Optically Coupling A Photographic Camera With A Viewing Device", now U.S. Pat. No. 4,157,216, an adapter which does accomplish the primary object of the present invention. However, the Plummer adapter utilizes a lens system in combination with a light diffusing element to spread to optical viewing device exit pupil so that its size matches that of the camera taking lens entrance pupil and to improve the uniformity of illumination over the camera taking and viewing system. Although the Plummer adapter is satisfactory, it is relatively expensive and complex. Therefore, there exists a need for a simplified, inexpensive adapter for accomplishing the primary object of the present invention.
Other objects of the invention will in part be obvious and will in part appear hereinafter. The invention accordingly comprises the apparatus possessing the construction, combination of elements, and arrangement of parts which are exemplified in the following detailed disclosure.